[PATCH 6.1 042/162] arm64: cpufeature: Fix CLRBHB and BC detection

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kristina Martsenko <kristina.martsenko@xxxxxxx>

commit 479965a2b7ec481737df0cadf553331063b9c343 upstream.

ClearBHB support is indicated by the CLRBHB field in ID_AA64ISAR2_EL1.
Following some refactoring the kernel incorrectly checks the BC field
instead. Fix the detection to use the right field.

(Note: The original ClearBHB support had it as FTR_HIGHER_SAFE, but this
patch uses FTR_LOWER_SAFE, which seems more correct.)

Also fix the detection of BC (hinted conditional branches) to use
FTR_LOWER_SAFE, so that it is not reported on mismatched systems.

Fixes: 356137e68a9f ("arm64/sysreg: Make BHB clear feature defines match the architecture")
Fixes: 8fcc8285c0e3 ("arm64/sysreg: Convert ID_AA64ISAR2_EL1 to automatic generation")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Kristina Martsenko <kristina.martsenko@xxxxxxx>
Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230912133429.2606875-1-kristina.martsenko@xxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/arm64/include/asm/cpufeature.h |    2 +-
 arch/arm64/kernel/cpufeature.c      |    3 ++-
 arch/arm64/tools/sysreg             |    6 +++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -670,7 +670,7 @@ static inline bool supports_clearbhb(int
 		isar2 = read_sanitised_ftr_reg(SYS_ID_AA64ISAR2_EL1);
 
 	return cpuid_feature_extract_unsigned_field(isar2,
-						    ID_AA64ISAR2_EL1_BC_SHIFT);
+						    ID_AA64ISAR2_EL1_CLRBHB_SHIFT);
 }
 
 const struct cpumask *system_32bit_el0_cpumask(void);
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -212,7 +212,8 @@ static const struct arm64_ftr_bits ftr_i
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_HIGHER_SAFE, ID_AA64ISAR2_EL1_BC_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_CLRBHB_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_BC_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
 		       FTR_STRICT, FTR_EXACT, ID_AA64ISAR2_EL1_APA3_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -484,7 +484,11 @@ EndEnum
 EndSysreg
 
 Sysreg	ID_AA64ISAR2_EL1	3	0	0	6	2
-Res0	63:28
+Res0	63:32
+Enum	31:28	CLRBHB
+	0b0000	NI
+	0b0001	IMP
+EndEnum
 Enum	27:24	PAC_frac
 	0b0000	NI
 	0b0001	IMP





[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux